The present invention relates to a heat exchanger, and in particular to a fluid pipe for use in a heat exchanger.
Heat exchangers are well known in air conditioning systems, refrigerant systems, and as radiators (for example, in motor vehicles). Such known heat exchangers include a pair of header tanks or manifolds which are fluidly connected by fluid pipes which extend between the manifolds. In general, the fluid pipes are formed by extrusion and then brazed to the manifolds. The fluid pipes may be extruded with two or more adjacent, longitudinally extending, channels. In an alternative arrangement, as described in EP-A-0302232 and EP-A-0646231, the fluid pipes may be formed from sheet metal by folding and then soldering.
It is an object of the present invention to provide an improved fluid pipe for a heat exchanger.
A fluid pipe in accordance with the present invention for fluid flow between a pair of manifolds of a heat exchanger and which is formed from a single piece of sheet metallic material having a cladding on at least one surface, comprising a first side wall having a first portion and a second portion; a second side wall extending substantially parallel to and spaced from the first side wall; a pair of end walls connecting the first and second side walls; first, second and third internal walls positioned internally of the first and second side walls and the end walls, the first, second and third internal walls being spaced apart and spaced from the end walls, and extending between the first and second side walls, the first internal wall being of double the thickness of the sheet and being positioned intermediate the second and third internal walls; a first planar side portion connecting the first and second internal walls and contacting a first planar part of the internal surface of the second side wall; a second planar side portion connecting the first and third internal walls and contacting a second planar part of the internal surface of the second side wall; a third planar side portion connected to the second internal wall and contacting a planar part of the internal surface of the first portion of the first side wall; and a fourth planar side portion connected to the third internal wall and contacting a planar part of the internal surface of the second portion of the first side wall.
The present invention also includes a heat exchanger having a number of fluid pipes in accordance with the present invention.
The present invention provides fluid tubes which are formed by rolling and folding from a sheet of metallic material which is clad on at least one surface. On subsequent assembly into a heat exchanger, the fluid pipes and the other components of the heat exchanger can be brazed together in a single brazing operation. The fluid pipes of the present invention have increased strength over known arrangements.